AIMS OF THE STUDY To evaluate the state-of-the-art of 14 specific proteins measurement; to evaluate the laboratories' performance and the degree of harmonization in reporting results of participants in the External Quality Assessment Program of the Centre of Biomedical Research (CRB). METHODS Overall and system-related inter-laboratory analytical variability (mean CVs%) and between-system differences (mean bias%) were evaluated from data of six EQA cycles 2013-2018. Moreover, we evaluated the analytical performance of participants as well as the units used to express proteins results. RESULTS Overall inter-laboratory variability ranged from 3.8% for haptoglobin (HPT) to 12.5% for α1-antitrypsin (AAT) and decreased for IgA, α2-macroglobulin (A2M) and transferrin (TRF). Mean CVs% were generally higher for Siemens BN and Beckman Immage immunonephelometric systems, but <7.0% for all proteins. Mean bias > 7.0% was observed for BN (IgA, C4, AAT, transthyretin TTR), Siemens Vista (IgA, C4) and Immage (C4), whereas mean bias < -7.0% was found for Immage (AAT), Beckman AU (IgM) and Roche Cobas (C4, TTR, C-reactive protein). The laboratories' performance within the limits ranged from 85.1% of albumin (ALB) to 97.2% of HPT. The census of units employed in 2018, demonstrated that ~ 70% of laboratories still express the results in mg/dL. CONCLUSIONS Despite a reduction in inter-laboratory variability for some proteins, different analytical systems showed both proportional and constant bias between methods. Units used by participants have not been substantially changed and dL is still largely used. The CRB EQA Program, with its performance data sets, is a valuable resource for laboratories and IVD manufacturers and support the goals of harmonization.

中文翻译：

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通过外部质量评估计划检查的14种特定蛋白质测量的性能评估。

研究目的评估14种特定蛋白质测量的最新技术；在生物医学研究中心（CRB）的外部质量评估计划的参与者报告结果中评估实验室的绩效和协调程度。方法根据2013-2018年六个EQA周期的数据评估整体和系统相关的实验室间分析变异性（平均CVs％）和系统间差异（平均偏差％）。此外，我们评估了参与者的分析性能以及用于表达蛋白质结果的单位。结果实验室间的总体变异范围从触珠蛋白（HPT）的3.8％到α1-抗胰蛋白酶（AAT）的12.5％，而IgA，α2-巨球蛋白（A2M）和转铁蛋白（TRF）的降低。对于Siemens BN和Beckman Immage免疫比浊法系统，平均CVs％通常较高，但对于所有蛋白质，均小于7.0％。BN（IgA，C4，AAT，运甲状腺素蛋白TTR），Siemens Vista（IgA，C4）和Immage（C4）的平均偏倚> 7.0％，而Immage（AAT），Beckman AU的平均偏倚<-7.0％ （IgM）和罗氏Cobas（C4，TTR，C反应蛋白）。实验室的性能范围为白蛋白（ALB）的85.1％至HPT的97.2％。2018年使用的单位普查表明，仍有约70％的实验室仍以mg / dL表示结果。结论尽管某些蛋白质的实验室间变异性有所降低，但不同的分析系统显示了方法之间的比例偏差和恒定偏差。参与者使用的单位没有实质性改变，并且dL仍被大量使用。